.\" Copyright (c) 2002-2004 Tim J. Robbins
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: src/lib/libc/locale/mbsrtowcs.3,v 1.6 2005/01/11 20:50:49 ru Exp $
.Dd July 21, 2004
.Dt MBSRTOWCS 3
.Os
.Sh NAME
.Nm mbsnrtowcs ,
.Nm mbsnrtowcs_l ,
.Nm mbsrtowcs ,
.Nm mbsrtowcs_l
.Nd "convert a character string to a wide-character string (restartable)"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In wchar.h
.Ft size_t
.Fo mbsnrtowcs
.Fa "wchar_t *restrict dst"
.Fa "const char **restrict src"
.Fa "size_t nms"
.Fa "size_t len"
.Fa "mbstate_t *restrict ps"
.Fc
.Ft size_t
.Fo mbsrtowcs
.Fa "wchar_t *restrict dst"
.Fa "const char **restrict src"
.Fa "size_t len"
.Fa "mbstate_t *restrict ps"
.Fc
.In wchar.h
.In xlocale.h
.Ft size_t
.Fo mbsrtowcs_l
.Fa "wchar_t *restrict dst"
.Fa "const char **restrict src"
.Fa "size_t len"
.Fa "mbstate_t *restrict ps"
.Fa "locale_t loc"
.Fc
.Ft size_t
.Fo mbsnrtowcs_l
.Fa "wchar_t *restrict dst"
.Fa "const char **restrict src"
.Fa "size_t nms"
.Fa "size_t len"
.Fa "mbstate_t *restrict ps"
.Fa "locale_t loc"
.Fc
.Sh DESCRIPTION
The
.Fn mbsrtowcs
function converts a sequence of multibyte characters, pointed to indirectly by
.Fa src ,
into a sequence of corresponding wide characters. It stores at most
.Fa len
of them in the
.Vt wchar_t
array pointed to by
.Fa dst ,
until it encounters a terminating null character
.Pq Li '\e0' .
.Pp
If
.Fa dst
is
.Dv NULL ,
no characters are stored.
.Pp
If
.Fa dst
is not
.Dv NULL ,
the pointer pointed to by
.Fa src
is updated to point to the character after the one that conversion stopped at.
If conversion stops because a null character is encountered,
.Fa *src
is set to
.Dv NULL .
.Pp
The
.Vt mbstate_t
argument,
.Fa ps ,
is used to keep track of the shift state.
If it is
.Dv NULL ,
.Fn mbsrtowcs
uses an internal, static
.Vt mbstate_t
object, which is initialized to the initial conversion state
at program startup.
.Pp
The
.Fn mbsnrtowcs
function behaves identically to
.Fn mbsrtowcs ,
except that conversion stops after reading at most
.Fa nms
bytes from the buffer pointed to by
.Fa src .
.Pp
While the
.Fn mbsrtowcs
and
.Fn mbsnrtowcs
functions use the current locale, the
.Fn mbsrtowcs_l
and
.Fn mbsnrtowcs_l
functions may be passed locales directly. See
.Xr xlocale 3
for more information.
.Sh RETURN VALUES
The
.Fn mbsrtowcs
and
.Fn mbsnrtowcs
functions return the number of wide characters stored in
the array pointed to by
.Fa dst
if successful, otherwise it returns
.Po Vt size_t Pc Ns \-1 .
.Sh ERRORS
The
.Fn mbsrtowcs
and
.Fn mbsnrtowcs
functions will fail if:
.Bl -tag -width Er
.It Bq Er EILSEQ
An invalid multibyte character sequence was encountered.
.It Bq Er EINVAL
The conversion state is invalid.
.El
.Sh SEE ALSO
.Xr mbrtowc 3 ,
.Xr mbstowcs 3 ,
.Xr multibyte 3 ,
.Xr wcsrtombs 3 ,
.Xr xlocale 3
.Sh STANDARDS
The
.Fn mbsrtowcs
function conforms to
.St -isoC-99 .
.Pp
The
.Fn mbsnrtowcs
function is an extension to the standard.
